Methyl Jasmonate Modulates Feeding Behaviors and Hypothalamic Expression of the Orexin 1 Receptor in Rats.

Objectives: Active plant ingredients have been successfully used in modern medicine to control appetite and energy hemostasis. This study was designed to evaluate the efficacy of the phytohormone methyl jasmonate (MJ) on food-related behaviors in rats.

Materials and methods: Adult male Wistar rats were randomly divided into different groups (7 rats) and infused intracerebroventricularly (i.c.v.) with MJ vehicle (DMSO) or MJ (2.5, 5 and 10 μg/rat). Then, the individual rats were placed in an automated open field-like apparatus to assess a 12-h food-related activity in light and dark times. After behavioral tests, immunofluorescence staining of the orexin 1 receptor (Orx1R) was studied in the hypothalamus of rats.

Results: MJ (2.5, 5, and 10 μg/rat) administration significantly decreased food intake in the light and dark phases compared with the control group. Moreover, all the MJ-treated groups exhibited a decrease in visits to food containers at the light and dark times (p < 0.001). In addition, rats infused with MJ at 5 μg and 10 μg spent less time in the ports of food containers in the light and dark phases in comparison with control rats. Time in zone-related to food and locomotor activity was significantly decreased in the MJ (5 μg) groups during the light time and in all MJ-injected groups in the dark time. Moreover, hypothalamic expression of Orx1R in rats treated with MJ (5 μg) was significantly lower as compared to the control group.

Conclusion: Overall, the results indicated the potential of MJ to modulate feeding-related behavior and Orx1R expression in the hypothalamus of rats.